\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,latexsym}
\usepackage{hyperref}
\usepackage[nofonts]{ctexcap}
\usepackage{setspace}
\usepackage{graphicx}
\usepackage{fix-cm}
\usepackage{enumerate}
\usepackage{float}

\newcommand{\bigsize}{\fontsize{25pt}{20pt}\selectfont}
\setCJKmainfont[BoldFont=STFangsong]{STFangsong}
% Page length commands go here in the preamble
\setlength{\oddsidemargin}{-0.25in} % Left margin of 1 in + 0 in = 1 in
\setlength{\textwidth}{7in}   % Right margin of 8.5 in - 1 in - 6.5 in = 1 in
\setlength{\topmargin}{-.75in}  % Top margin of 2 in -0.75 in = 1 in
\setlength{\textheight}{9.2in}  % Lower margin of 11 in - 9 in - 1 in = 1 in

\newtheorem{theorem}{Theorem}
\newtheorem{definition}{Definition}

\renewcommand{\baselinestretch}{1.5} % 1.5 denotes double spacing. Changing it will change the spacing

\setlength{\parindent}{0in}
\begin{document}
\CTEXsetup[format={\Large\bfseries}]{section}
\CTEXsetup[number={\chinese{section}}]{section}

\input{front}

\pagestyle{plain}
\tableofcontents
\newpage

\input{content}
\end{document}
